There exists a variety of techniques for determining a position for a mobile-station or some other wireless communication device. These positioning techniques include the well-known Cell/Sector ID method, Enhanced Observed Time Difference (E-OTD) and Assisted Global Positioning System (AGPS).
The Cell/Sector ID method involves determining a position of a mobile-station based on the identity of a base station currently serving the mobile-station, i.e., serving base station. FIG. 1 depicts a cell 10 associated with a base station, not shown, that is currently providing wireless communication services to a mobile-station 12. The identity of the serving base station, the cell associated with the serving base station, and the location of the cell are known by the wireless communication network to which the base station belongs. Based on these known parameters, the Cell/Sector ID method can be used to determine an approximate position for mobile-station 12. Specifically, if cell 10 is a non-sectorized cell, mobile-station 12 would be determined to be positioned at the centroid of cell 10 using the Cell ID method. If cell 10 is a sectorized cell, mobile-station 12 would be determined to be positioned at the centroid of the sector in which mobile-station 12 is currently located using the Sector ID method.
The average errors associated with positions determined using Cell/Sector ID method for a non-sectorized and a sectorized cell would be   1      2  R and 0.433R, respectively, where R represents a radius of cell 10. Depending on the radius of cell 10, the average error associated with the Cell/Sector ID can be quite large and, thus, unacceptable. For example, if cell 10 has a radius R of 5 km, then the average error for a non-sectorized and a sectorized cell would be about 3500 m and 2200 m, respectively.
The E-OTD and AGPS methods are much more accurate positioning techniques than the Cell/Sector ID method. However, the E-OTD and AGPS methods are not backward compatible from the perspective of second generation mobile-stations. That is, the E-OTD and AGPS methods require the mobile-station to have additional hardware/software not currently in second generation mobile-stations.
Accordingly, there exists a need for a positioning technique that is backward compatible and more accurate than the Cell/Sector ID method.